Frequency changer



Oct. 25, 1927.

Filed Nov. 22, 1919 2 Sheefs-Sheet 1,646,662 Oct. 25,1927. w. C ROE v FREQUENCY CHANGER Filed Nov. 22, 1919 2 Sheets-Sheet 2 Elli- )6 AMA/\MMM V U \JUWU PATENT. OFFICE.

WILLIAM C. ROE, OI PITTSBURGH, PENHSYL'V ANIA.

FREQUENCI omens.

Application filed November 22, 1918. Serial No. 889,886.

This invention relates to frequency changers, and more particularly to a frequency changer by. means of which an alternating current of high frequency may be cut down, or reduced, to a suitable comparat velylow frequency for operating bell ringing circuits and for operating any electroresponsive devices which it may be expedient to operate at a lower frequency.

Other important objects will hereinafter be made apparent as the descriptlon of the invention proceeds.

In describing the invention in deta1l,ref erence is herein had to the accompanying drawings, forming a part of this specification, in which similar characters of reference indicate corresponding parts throughout the several views, in which- Figure 1 is a plan view of certain apparatus embodying my invention positioned in a cabinet;

Figure 2 is a plan view of the cabinet showing the binding posts for the source 0 current and the low frequency current;

Figure 3 is a diagram of the wiring connections as embodied in my invention, and

Figure 4 is an illustration of a 60 cycle 6 current wave train showing, by shading, the

pulsations selected to obtain 20 cycles, using a reed tuned to a natural frequency of 40 cycles. a

Referring particularly to Flg. 3, the source of alternating current is supplied at binding posts 1 and 2. A vibrator reed 3 is cause to vibrate continuously by the current passing through a vibrator coil 4 and has an adjusting screw 3 to which leads a conductor from one of said binding posts, as A suitable condenser 5 and a resistance coll 6 are connected in series and shunted across the contacts to prevent sparking at the contact points, and also to insure the opening andv closing of the vibrator contacts at substantially zero current, and further creating a continuous and very satisfactory wave for bell ringing apparatus. The transformer 7 is used'to obtain the desired voltage and insulate the secondary circuit from the power circuit. It will be noted in the embodiment of my invention herein illustrated that the primary of the transformer has one or more windings adapted'to be connected either in multiple or series, as maybe neces sary, to adapt it to different primary voltages. Also the secondary of the transformer has a winding which may comprise a plurality of sections and which sections may be as indicated adapted to be connected either in multiple or series and attached to termirials so that by using different windin combinations, practically any voltage can e obtained from zero to the transformer maximum; the insertionof'a lamp 8 in the transuntil.

a point is found where the vibrator reed vibrates substantially at its natural frequency period, whereupon it may be-sub stantially sparkless and self starting.

It will be understood that such a reed as illustrated vibrating at 40 cycles'per secondmay thus be adjusted to close the contact for I every third positive pulsation and every third negative pulsation, making the frequency 20 cycles through the transformer when the source of current is of 60 cycles frequency.

By referring to the foregoing description and to the drawings, particularly Figs. 1, 3

and 4 it will be seen that current is only supplied to the primary of the transformer 7 whenever the contacts 3-3 of the vibrator 1 i are closed.

Referring particularly to Fig. 4 it will be seen that in the case where a p'roperlyadjusted vibrator is employed toconvertcilr-a rent abstracted from a (SO-cycle sourcejto a current having the-operative characteristics of twenty cycles, these contacts 33.are

only closed one-third of the time. lows, therefore, that the reed 3 in its excursions toward the pole face of the electromagnet and receding therefrom will have that excursion which takes place to the left of the indicated position of the reed, Figs.

1 and 3, for a period of time which is twice,

It fol loo as great as the period of time when the con- 1 tacts 33 are closed and the reedin the position shown or to the right thereof. In

the above reference to the directions right, and left, the same 15 to be taken as viewin the vibrator as shown in Fig. 3. The ree is adjusted in any of the well-known ways for adjusting reeds to vibrate at a given rate and in its movement from the longer to the shorter excursion it comes up against the end of the contact screw 3 when traversing the normal position occupied by the reed as illustrated. It is well known that this will have the effect of shortening the reed so far as its rate of travel is concerned, and this efiect will be maintained as long as the reed is on that excursion wherein it maintains contact with the contact screw 3 and presses against it. It is plain from the above also that the reed in making the ion er excursion takes twice as long as the ma ing of the shorter excursion, that is, an even multiple of the time consumed in the making of the shorter excursion.

The frequency changer can be well fitted into a cabinet container 10 and have its connections brought to binding posts 1 and 2 for the source of current, and to posts 11, 12

and 13 for the low frequency current on the .upper side.

Sockets 14 and 15 are provided for the reception of lamps Sand 9, the latter being located in the power circuit, as shown.

In practice, the electric current, as, for 1nstance, 110 volts, 60 cycles, from the primary source connected to binding posts 1 and 2, traverses a circuit which comprises the conductor leading from post 2, the adjusting screw 3 to which said conductor is connected, the reed 3, and the frame of the vibrator coil. At this point the current divides, a portion thereof passing to and through the winding of the vibrator coil 4, the lamp 9, and thence to binding 1post 1, while the other portion passes to an t irough the primary of the transformer, thence through the lamp 8 to binding post 1. The lamp 9 may have its capacity limited to the extent that just sufficient current is permitted to flow to and through the vibrator winding 4 to keep the reed 3 in vibration, whereas the lamp 8 may be of any capacity required to suit the current desired.

While I have illustrated and described a specific embodiment of my invention, for the purpose of explaining the same, it will be obvious that extensive departures may, be made from the specific embodiment herein illustrated and described, without departing from the spirit of my invention whose sco e is defined in the appended claims.

l aving thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is:

1. In an alternating current system, the combination with a sourceof. alternatin current, a current delivery circuit, a ree Whose natural periodicity of vibration is different from the periodicity of alternating current from the said source, and operable thereby to vibrate at a rate fractional thereof, current modifying means between the said source and the said circuit, said reed when so vibrated so controlling the said means as to cause the resultant current flow-- ing in the delivery circuit to have a freet1onal frequency operative characteristic to the unmodified current from the said source.

The system as set forth in claim 1 comprising a reed operating means energized by current from the said source modified by the said reed operating means. A

3. In an alternating current system, the combination with a source of alternating current, a current deliver circuit, a reed whose natural periodicity o vibration is diiferent from the periodicity of alternating current from the said source, and operable thereby to vibrate at a rate fractional thereof, ourrent modifying means between the said source and the said circuit, said reed when so vibrated so controlling the said means as to cause the resultant current flowing in the delivery circuit to have a fractional frequenc operative characteristic to the unmodi ed current from the said source, wherein the reed vibration is at a rate fractional to the -periodicity of the impressed alternating current in the ratio of 1 .to a larger odd number.

4. The alternating current system .as in claim 1 comprising reed vibration controllin means operable to cause the vibrating ree to make a slower excursion in one direction from an intermediate position than in the opposite direction, the longer excursion consuming substantially an even multiple of the time consumed in the making of the shorter excursion.

5. In an alternating current system, the combination with a source of alternating current, a current deliver circuit, a reed whose natural periodicity o vibration is different from the periodicity of alternating current from the said source, and operable thereby to'vibrate at a rate fractional thereof, current modifying means between the said source and the said circuit, said reed whenso vibrated so controlling the said means as to cause the resultant current flowing in the delivery circuit to have a fractional frequenrgy operative characteristic to the unmodi ed current from the said source, comprising reed vibration controlling means operable to cause the vibrating reed to make a slower excursion in one direction from an intermediate position than in theopposite direction, the longer excursion consuming substantially an even multiple of the time consumed in the making of the shorter excursion, the said jreed actuating the said current modifying means when its free end traverses an intermediate point in its path in either direction.

6. In an alternating current system, the combination with a source of alternating current, a current delivery circuit, a reciprocable element whose natural periodici is different from the periodicity of a ternating current from the said source, and operable thereby to reciprocate at a rate fractional thereof, current modifying means between the said source and the said circuit, said reciprocable element when so operated so controlling the said means as to cause the resultant current flowing in the delivery circuit to have a fractional freguency operative characteristic to the unmodi ed current from the said source.

7. In an alternating current system, a source of alternating current, a reciprocatory type electrical motor, current modifying means operable by the said motor, a service 8. In an alternating current system, the.

combination with a source of alteranting current, a current delivery circuit, a reed whose natural periodicity of vibration is different from the periodicity of alternating current from the said source, and operable thereby to vibrate at a rate fractional thereof, current moidfying means between the said source and the said circuit, said reed when so vibrated'so controlling the said means as to cause the resultant current flowing in the delivery circuit to have a fractional frequenleiy operative characteristic to the unmod' ed current from the said source, in combination with an electromagnet for operating the said reed when energized by current from the said source, in combination with circuit connections leading from the current delive circuit to the said magnet whereby modi ed current from the said source is delivered to the magnet.

9. In an alternating current system, the combination with a source of alternatin current, a current delivery circuit, a ree whose natural periodicity of vibration is different from .the periodicity of alternating current from the said source, and o rable thereby to vibrate at a rate fractions. thereof, current modifying means between the said source and the said circuit, said reed when so vibrated so controlling the said means as to cause the resultant current flowing. in the delivery circuit to have a fractional uency operative characteristic to the unm ified current from the said source in combination with an electromagnet for operating the said reed when energized by current m the said source.

In testimony whereof I afiix my ature. WlLLIAM cl h on. 

